The 34-year-old Smith dropped the bombshell news at a Melbourne media conference on Tuesday, saying he'd been thinking about it since last year and "now is the right time for me to finish up".

"Last year, more than any other year, the Origin series in particular had an effect on me both physically and mentally," said Smith.

"I couldn't quite back up after any of those Origin matches and maybe that was a sign there that it was time, because I have always been very proud of my ability to back up."

Smith said those weekends, when unable to play for Melbourne, he was lying on the couch at home exhausted physically and mentally, and he believed few realised the toll playing at that level took.

Smith's exit follows with the representative retirements of fellow Australian and Queensland greats Johnathan Thurston and Cooper Cronk, which were announced last year.

Since making his debut for Queensland in 2003, Smith has played a record 42 Origins for the Maroons and has been captain of the side since 2012.

In that period he has missed just one game - the series opener in 2010 due to injury - and won a record 26 matches.

Since playmaker Thurston's debut in 2005, the pair have played a crucial role in guiding the Maroons to 11 series wins in 12 years.

Smith's exit is likely to springboard Brisbane hooker Andrew McCullough into a Queensland Origin debut in the June 6 series opener at the MCG, while Jake Granville of the Cowboys could be another option.

Darius Boyd, Billy Slater or Greg Inglis are the most likely candidates to take over the captaincy, however Boyd has battled form and fitness at Brisbane this season.

Queensland coach Kevin Walters paid glowing tribute to Smith, saying the Maroons would not be able to replace him with anyone similar.

"I thought his performance in game 3 of last year was one of the best I have seen from anyone at that level and at age 34 that speaks volumes," said Walters.